1. Field of the Invention
The present invention relates to heterogenous optically initiated gas phase reactions conducted at least partially in the presence of a finely divided energy sink.
2. Description of the Prior Art
There are many different methods of catalytically initiating chemical reactions. However, in most cases, the efficiency is very low and there is little or no reaction selectivity among closely related reactants such as isotopes. Thermally induced chemical reactions lead to the excitation of all degrees of freedom of the molecule, the translational, vibrational and rotational degrees of freedom being generally in thermodynamic equilibrium. Thus, there is considerable energy lost non-productively, and molecules excited at equilibrium are characterized by a potentiality to acquire activation energy to excite the bond or group with the lowest activation energy.
Recently, much progess has been made in photon induced catalysis due to the development of tuning, control and stabilization of laser radiation over a widening range of available wavelengths in the visible, untraviolet and infrared regions of the spectrum. In photon activated chemical reactions, the excitation can be selectively localized to individual bonds. Molecules initiated by laser radiation and having a vibration-mode temperature, for example, reaching tens of thousands of degrees can enter into controlled chemical reactions at rates greatly exceeding the rates of the thermal vibrational-transational relaxation. Thus, laser initiated chemical reactions are characterized not only by selectivity but also by the discrete separation of the electronic, vibrational and translational temperatures. Moreover, under controlled conditions, thermodynamic equilibrium can be perturbed and internal degrees of freedom can be selectively excited, the molecule entering the chemical reaction retains an excited mode that is resonantly excited by the frequency of the laser radiation.
Another advantage of photon generated reactions is the absence of conventional catalysts which are both expensive and subject to fouling or poisoning requiring shut down of the equipment for reactivation or replacement of the catalyst charge. Heterogenous reactions in the gas phase over solid catalysts is involved in two critically important technologies; protection of the environment by aftertreatment of stationary and non-stationary pollution emissions and synthetic fuels such as in the coal gasification process.